Fertile Floods: Croatia's Wetlands (2018) - full transcript

A picturesque region in the Balkans

packed with strange customs

birds eat with spoons

horses go bathing and a big

mouth go swimming in the woods

in the middle of Croatia there

is an abundance of water

the unpredictable waters of

the Sava know no restrictions

and create an amphibian world

flooded for months at a time the wetlands

are home to swarms of young creatures

like the ugly ducklings

piggyback chicks and builders

busy grooming themselves

in the floodplains large birds catch

fish and large fish catch bird

here people live with the water as was usual

in many parts of Europe centuries ago

at a time when rivers could meander

as they pleased

an ancient cultural landscape in which many

domesticated animals can wander freely all year round

like the deer in the forests

and the beavers in the water

that landscape shows us today

what flood protection can mean

[music]

the most plentiful tributary of the Danube

has its headwaters in the julian alps of Slovenia

fed from glaciers snow and ice one of its stems has

its source in the foothills of Mount Airy Bluff

this is where the Sava river begins its

over 940 kilometer journey

emerald-green Springs produce crystal-clear

groundwater like miniature volcanoes

before it got this far it trickled down

underground through the mountains

it's still winter up here

everything is sheathed in ice

even lake behind where the two stems of the

Sava join forces still has a coating of ice

from here the Sava continues as a tumbling mountain

torrent towards the Danube and the Black Sea

to save energy in this gushing River the trout

and speckled trout aim into the current

despite the bitter cold of the winter

many parts of the Sava remain ice-free

where he becomes shallower it freezes

over from the banks towards the center

but the fast flowing current will not permit

the ice to cover the surface completely

mountain streams like this are the preferred

hunting ground of a rather special bird

the white throated dipper relies on the streams

not freezing over completely in the winter

it doesn't just dip its head into the water

to hunt for amphipods or insect larvae

the Dipper is the only songbird that can

swim and can dive for up to 30 seconds

it even takes a dive into the gushing Sava

where a Danube salmon has already caught its

lunch but is having difficulty swallowing it

there was a time when this predatory fish that grows up to 1.8

metres in length was ubiquitous throughout the Danube area

today the Danube salmon is less frequent

it needs fast flowing well oxygenated

rivers with plenty of gravel to breed in

in many places those rivers have been

dammed with barges and lock systems

this is why the untamed Sava is a

crucial retreat for the Danube salmon

the Sava is still passing through

mountainous country but soon the

gradient becomes less obvious and the

river completely changes its character

as it passes through Slovenia Croatia

Bosnia Herzegovina and Serbia

the lively mountain stream from the

eastern Alps becomes a leisurely

meandering river that joins

the Danube at Belgrade

halfway along southeast of Zagreb it snakes through

flat plans with only the slightest gradient

here in plaza vena lies the

long scope olia nature reserves

in one of the last contiguous

River landscapes in Europe

in the cold winter many of the side arms of the

sava wetlands are frozen to a large extent

in the Balkans the summer is much warmer than in

Central Europe but the winter can be very hard

there are not many sections of this tranquil

stretch of water that stay free of ice

they're only superficially frozen and

many of the fish spend the winter here

as do the great white heron they may look exotic but

they can deal with extremely frosty temperatures

since they don't only live off fish they don't

have to migrate when the waters freeze over

they find enough mice and other

small animals under the snow

and this fox is hoping his luck ease in today

the open sections of the Sava are

a center of attraction for many

mute swans the largest waterfowl in

Europe get social during the winter

sometimes dozens of them will congregate

around the unfrozen arms of the river

in places like this no movement in the water

will go unnoticed by the white and grey herons

after all it might be a fish and in these

temperatures every calorie is precious

and worth an argument

and this wild boar does not want to be left out

so he goes over to sort the herons out

and disappears into the extensive

forests of the Sava wetlands

the Nature Reserve is not only

home to centuries-old Slavonia oak

whose particularly durable wood is highly

sought-after for furniture and wine barrels

it's also where the best ham is

domiciled so the saying goes

the winter resistant Europe olia pigs with

their layer of fat up to 15 centimetres thick

live here all year round and root

around in the woods looking for acorns

during the Balkan war at the beginning of the 1990s

this ancient species of animal was nearly made extinct

but the robust original Europe aalia's are an

essential source of genetic material for pig breeding

fortunately it was possible to save them

and with them the traditional

grassland farming by the sava

an ancient cultural bio diverse landscape

artificial canals cut their

way through the wetlands

but the neatly felled trees

were not the work of humans

fresh tracks indicate that they're

still active even in the cold season

beavers do not hibernate these large

rodents have to eat regularly

they've stocked their underwater

ladders for difficult times

but wherever possible they prefer to

save their energy and eat fresh bark

even if the way to the next

snack is a little slippery

even the Magpies cantake a slide

now that it's slowly beginning to thaw some

small tip bits are becoming accessible

the great bitten likes to stalk along the edge of the reeds where

there are often breaks in the ice looking for unmoving fish

while Magpies as omnivores can survive in the

cold season by feeding on vegetarian meals

the great bitten needs its meat licious

then spring comes and in the julian alps where

the Sava has its source everything is thawing

water from the massive catchment

area tumbles over the cliffs

one great torrent is making its way

in the plaza vena plain the water masses build

up the entire Sava basin fills up sometimes as

much as 10 metres above the normal level

although it looks like a natural disaster this is actually

saving the towns along the Sava from urban flooding

the Sava wetlands act as a detention basin over

600 square kilometres is flooded every year

like an enormous sponge the alluvial forests soak

up the water from around 10 billion bathtubs

in the past many River landscapes

around Europe looked like this

these trees often spend several weeks

and months standing in the water

without these floodplains towns like Zagreb

and Belgrade would frequently be washed out

many animals benefit from the flooding

no less than 15 species of

amphibians like the moor frog

these 7 centimeter long frogs leave their

winter quarters on mass in the spring

and for the spawning season the

male's take on a blue color

these flooded meadows provide plenty of food

herons fish while beside them

the wild boar graze on

fresh greens in the water

or dig in the soggy soil for

insect larvae and roots

even the torah' polio

pigs wade in the marsh

with their powerful snouts

they plow the river landscape

they're digging action breaks up the heavy soil allowing

fresh grass to establish itself in the nutrient-rich mud

by maintaining this traditional

meadow management system

the inhabitants of the Sava region have found a way of

making the most of the wetlands despite regular flooding

they live with the water rather

than fighting against it

since the level can rise by 10 metres

overnight the houses are built on embankment

and usually 2 storeys high when the floods

come the inhabitants move up to the top floods

the Chi got village has 70 timber houses

and used to be home to 300 people there

are now only a hundred and twenty

but they have sub-tenants there are over

40 pairs of storks nesting on the roofs

g-gosh was christened Europe's first stork village

the inhabitants support the storks and provide

platforms for them to build their nests on

the alluvial forests are a plentiful

source of nest building materials

a stork's nest can have a diameter of 2 meters

many are the work of successive stork generations

when the partner returns carrying building materials

he or she is greeted with bill clattering

the nest is also the mating location

a balancing act high up on the roof

while the storks actively seek human

habitations to build their nests

others prefer the privacy of the alluvial forest

after the winter the mute swans

give up their social gatherings

they're strict vegetarians and

mainly live off aquatic vegetation

but when a pair start

exchanging aquatic undergrowth

they're collecting building materials

branches and twigs form the base construction

the greenery is for the padding

the swan couples like to build

their nests that are big enough for five

to seven eggs on small islands away from

the banks to prevent the Foxes getting close

the crested grebe have already laid their eggs in the

floating nest made of reeds branches and water plants

as underwater hunters they catch small fish

interspersed with aquatic insects and crayfish

this one has caught a

particularly bulky specimen

swallowing this large crayfish with its hard

shell and cumbersome pincers is quite a feat

once dinner is over the grebe

has to preen itself thoroughly

what looks like a heap of old sticks dumped in the

forest is in fact an architectural masterpiece

beavers build dams to

maintain a steady water level

the entrance to their Lodge is under

water to keep out land-based predators

they may not look very graceful a beaver

can weigh up to 40 kilograms which is

heavier than a roe deer but underwater

they cut a very streamlined figure

they propel themselves forwards with their

hind feet the scaly tail acts as a rudder

the beaver will gnaw at a large tree for

several days

once the tree has been felled that will

gorge themselves on the juicy leaves and

buds from the crown of the tree

thinner twigs up to the thickness of a pencil that's still

very soft are eaten completely with the wood and bark

many of the felled trees will

sprout again the next year

the larger branches are only used as

building materials for the lodge and Dam

this is what causes beaver Lakes

with constant water levels

these permanent water features created by beavers

are extremely important for the plants and

animals in the alluvial forests

the European pond turtle for example one of

12 reptile species in the Nature Reserve

these turtles prefer thick underwater

vegetation with muddy sediment

they usually mate in the water on dry

land it can be a risky affair

in summer beavers will mainly

eat juicy green vegetation

fresh herbs and foliage

buds and water lily roots

they generally only live off tree bark

in the winter when there's nothing else

a fully grown beaver needs a kilogram

of fresh vegetable matter every day

when they dive they can stay

underwater for a quarter of an hour

their nose and ears are closed off they can see because

their eyes are protected by an additional transparent skin

the lodge has now seen

the arrival of the kids

between April and June the female will give birth

to one to four kids with hair and their eyes open

the young spend the first month in

the living quarters of the lodge

for six to eight weeks they're subtle by the mother

as long as the kids are in the lodge they're safe

but out in the waters of the sava

terrifying predators are waiting

catfish can grow to 100 1/2 meters long

and weigh more than 50 kilograms

some have even been known to grow to three

metres in length and reach weights of

over a hundred and fifty kilogram

the sava wetlands are home to one of the

largest catfish populations in Europe

they're usually loners

but in spring there are

sometimes unusual gatherings

the focus is usually a group of overweight

females with swollen bellies full of spawn

a large female can lay up

to half a million tiny eggs

and yet these whirling catfish are not mating this

puzzling spectacle is perhaps a kind of foreplay

the mating act takes place only between

two catfish in private after the male

has created a spawning burrow in the

shallow water close to the bank

among thick underwater vegetation

there are many suitable places along the

sava the quiet side arms are often

overgrown with a thick mat

of pond and water lilies

they're juicy branches are nourishing

tidbits for the Beavers

and the broad floating leaves are a welcome

diving board for France hunting insects

in this way the Fertile waters of the wetlands are a

good source of food for many species and a nursery

one of the most common fish in the

Sava is not even from this area

in the densely vegetated shoreline pumpkinseed fish with

their black mark on the gill cover have found a hole

at the end of the 19th century the fish was

introduced in Europe from North America

and escaped from some garden ponds since it

breeds several times a year it was able to spread

rapidly across the continent

the pumpkinseed protects its

spawning burrows aggressively

it will even attack very large intruders

one level higher another baby has

just freed itself of its eggshell

stripe iya squeakers or baby boars its

siblings already swimming around the nest

the chicks of the crested grebe do not all

hatch out at the same time but a day apart

surprisingly the parents offer

their babies freshly pulled feathers

even order the chicks eat them

one explanation might be this it's

possible that the feathers protect the

tender stomach linings of the babies

against sharp fish bones

the first weeks the chicks spend a lot

of time in a cozy hollow of warm down

this protects them against the cold

water and the hot Sun

frequently the parents will go swimming

with the chicks on their banks

and they have even been known to dive with

but this grebe is just looking for a

more comfortable position on the nest

in their piggy back position the chicks are relatively

safe from predators in the air and in the water

the sava wetlands offer many different

possibilities for undisturbed nesting

some build floating nests where

they can bring up their young

another crested species the hoop hole find safe

breeding in tree hollows in the oak forests

here the young wait for their parents who take turns to

bring food mainly crickets beetles and larger caterpillars

in the alluvial forests the penduline tit hangs its nest from

a branch to build the nest it uses fine vegetable fibers

sometimes even spider's webs

the soft pouches used to be collected

for use as children's slippers

the who posed nest is now

attracting unwanted attention

there are strange noises in the hollow

a Starling is intent on stealing nesting material

and the Hoopoe keeps well out of the way

discretion is the better part of valor

but what does the Starling really want it

flies off without the nesting material

so the Hooper parents can carry

on with feeding their young in peace

two-thirds of the landscape olio Nature

Reserve is covered with alluvial forests

one third is wet meadowland which provides the

storks with a well-stocked larder to choose from

every adults talk requires a pound of food a

day and the chicks need more than twice that

so store parents have to transport

several kilograms of food every day

they poke around in the grass to find insects

and mice amphibians slugs and earthworms

if the meadows are under water they

catch crayfish and small fish their

stalks are characteristic of the Nature Reserve

there are over 700 pairs breeding here

they're constantly

repairing their nests this means they

can grow over the years to 4 metres in

height and can weigh up to 600 kilograms

after over a month of incubation the

young storks have hatched

at the beginning one of the parents will

always stay with the nest provide shade and

regurgitate tidbits for the clamoring babies

everywhere in the wetlands

there are newborn babies

after a good five weeks of incubation

the mute swan cygnets have hatched

in their grayish white plumage

they're anything but ugly ducklings

they preen themselves in the water

hands together with their parents in the nest

the swans distribute oil from their

preen gland all over their plumage

to make every single feather waterproof

soon after hatching the cygnets are expected

to find their own food in the water

the parents were there longer necks may

be able to reach deeper into the water

but that doesn't mean they're going

to give away any of their lunch

the wetlands are fertile along the banks of

the snaking Sava river there are cormorants

the water is teeming with fish

the larger catfish have retreated to quieter regions

the younger catfish are swarming

in the open water like tadpoles

catching amphipods and insect larvae

this way they confuse fish predators that

have to be able to concentrate on one target

there are predators hiding

everywhere in the wetlands

like this spotted eagle

that's just grabbing a pumpkin seed fish

the noisy cormorant colony where the birds brood

together high in the trees can be heard from a distance

the older fledglings extract their lunches

from deep inside their parents throat pouch

if it's very hot the parents also give them water

the diverse bird life in the

wetlands can't be taken for granted

the fine balance can easily be disturbed

this can be seen from the

crappier doll side arm

where grey heron and

spoonbills breed side by side

the heron are frequently seen in

Europe and even nest in large towns

the more rare spoonbills however

only frequent intact wetlands

at the end of the 1980s this sidearm was

drained and the spoonbills disappeared

fortunately there are now 120 pairs

here reading beside the herons

after the sidearm was returned to its natural

state the spoonbills returned within two years

and are now bringing up their

young again in this joint colony

and even the young have a spoon shaped bill

today attends of all the spoonbills in

Europe breed in crappy Adal

this is why the bird with the strange shaped beak

was honored as the symbol of the Nature Reserve

in the slit of the sidearm there are

other birds with odd-looking beaks

the Bill of the pied Avocet

bends upwards towards the tip

while the spoon bill uses its extremely

sensitive bill to search the riverbed

for aquatic insects crayfish and clams

the Avocet sifts for small

animals in the shallow silt

even the young chicks emulate this

my swing their heads to detect prey

since their tools dictate the way

they search and what they find

they do not infringe on each other's

territory in the crocodile sidearms

we're into midsummer in the wetlands

and the entire beaver family

has taken to the water

the youngsters are still a little

apprehensive about the water

and have to be encouraged to swim or are

even carried by the bank an adult and a

juvenile from last year are combing

their fur using the special combing claw

on their hind feet and applying oil to

making waterproof

they tend to spend several hours a day in the

water on average and can't afford to catch cold

on average the sava wetlands are flooded

for 32 a hundred days a year

it's not only in spring but in any month of the year

that powerful rainfall can cause it to burst its banks

and generate fertile habitats for many creatures

including the Osprey although it only weighs one other

half kilos is able to catch fish weighing two kilograms

after locating them with its eagle eyes from afar

and picking them out of the water

in the sava wetlands with their

plentiful supplies of fish the Eagles also have

ideal locations for their IRA's in the tall trees

normally they produce two to three chicks

these youngsters are already a few weeks old

allowing both the parents

to leave the nest regularly

to bring home enough food

for the family

the labyrinthine waters of the wetlands

are often murky so not all the fish

hunters need to have such good eyes as

the Eagles that hum from high in the sky

the large catfish have relatively poor

eyesight but their whole body and in

particular their long feelers is

covered with sensitive sense organs

this allows them to notice quickly in

the muddy sediment of the sidearms

if a competitor has already

staked out a good hunting ground

with their large mouths catfish can

catch not only fish and crayfish

their hearing is so sensitive that they can detect vibrations

outside the water and go to check out the hunting options

in the flooded alluvial forests the catfish

is looking for a particular hunting ground

there are reports of small dogs ending

up inside the jaws of the catfish

this is where pigeons come

down to the water to drink

they're flapping wings are a giveaway

that attacked was a failure

the pigeons are wary and don't allow themselves

to be dragged into the water that easily

they're still thirsty though and come back

a new opportunity for the catfish

the pigeons are forewarned

for they keep coming back

the third attack is a success

in the summer The Meadows are a blaze of red

a sea of poppies growing in

a field near the village

in agriculture in the Sava wetlands

the emphasis is on livestock breeding

but in some places arable

farming is also possible

peppers and sweet corn cobs

dry outside the houses

as they have done for hundreds of years

there's twittering coming from the

rafters Housemartins

in the protected environment of old

houses we find a whole colony

some of the Housemartins have

been here twice this summer

the others still have

to complete their nests

they build the walls of their nests

from inside using moist lumps of earth

until there is only their front door left open

there's a plethora of building

materials in the Sarver wetlands

thanks to the moist surroundings these Martens can

always find lumps beside puddles and on the banks of the

waters even in the hottest summer

it takes around a fourth life to build a nest

and then they lay up to five eggs in it

and up in the loft there's

a lively commotion

the mouse eared bats spend the

daylight hours up here squeaking

most of these are females and they will give

birth to their young here and bring them up

hundreds sometimes even thousands

of bats vie for the best places

holding on tight with their claws

they spend the day hanging upside

down under the wooden roof

there will swarm out after darkness

falls and go searching for food

thanks to their large ears they can locate

their prey in the dark by ultrasound

mainly all manner of insects

in these moist weapons there are many

different midges and flies moths and beetles

the floodplains of the sava are of importance

to the protection of birds throughout Europe

on the one hand they're the breeding area for

over a hundred and forty different bird species

numerous waterfowl like the snipe nest

in these moist meadows

but for migrating birds to the sava wetlands are one

of the most important rest areas on the continent

here they can plan a stopover to

recover from their long flights

and eat to their heart's content

all-in-all no less than 240 bird species

have been registered in the Nature Reserve

including the curl you

where the syrup olia pigs plow up the

sava mud in spring we now get fresh grass

a great benefit to the

powerful paws of inna horses

with their broad hooves they have no

difficulty walking over the soften ground

in the summer they like to enjoy

a cooling bath in the sava

since the start of spring the horses have lived

here without any human influence in the wetlands

with their fluctuating water levels

this is the ideal environment

for grass snakes

that can hunt mainly toads and

amphibians in the moist surroundings

the snake could hardly catch

healthy fish in the river

but when the water recedes from the

flooded Meadows the fish left behind in

the puddles virtually leaps straight

into the grass snakes mouth

this easy to catch prey also attracts stalks

onto the moist meadows and pasture land

they pick the juiciest insects

often they will follow the cattle on horses because as they move

around grazing they dislodge grasshoppers and other creatures

the storks benefit from these free roaming

domesticated animals in many ways

if there were no horses or cattle

here there will be fewer storks

on the one hand puddles of this

kind are maintained by them

because horses and other livestock wallow

in them and keep the muddy areas open

the sava wetlands though a considerable degree of their

diversity to the hungry stomachs of these large herbivores

without the help of these

natural mowing machines

the damp pastures would soon

degenerate into closed oak forests

this traditional pasture farming keeps

the ancient cultural landscape alive

and encourages Himura files like the stork to

breed here in large numbers

by the end of the summer there are more

storks living in g-gosh than people

in many nests for chicks are

produced sometimes even 6

when it's really hot the parents will dribble water

from their beaks into those of the chicks

and eating grass snakes find their

way from the swamp to the nest

and from there into a storks stomach

in the late summer early morning miss

rise over the Nature Reserve

a melancholy idle

when the sava wetlands of Croatia remind us

of paintings by famous landscape artists

and that is no coincidence because large

regions of Europe used to look like this

before the rivers were forced to behave

and flooding was normal

times when all over the continent riparian

wetlands could only be used naturally for grazing

this created landscape diversity has

still seen in the landscape olia puddles

and pools on moist meadows

mocchi sidearms and river meanders

traditional woodland and pasture

while the paws Avena horses spend their winter in

their stables the pigs stay outside all year round

in the autumn they're driven into the

woods where they mainly eat acorns

these woodland pastures keep the

forests open and free of undergrowth

and that produces park-like landscapes in the wetlands

when autumn arrives there's a

lot of action to see and here

during the last warm days of the year the squirrels

and foxes build up their layers of winter fat

and in the country by the sava

the Red Deer are heard bellowing

those from the posavina region are

some of the strongest in Europe

the most important time of the year is

fast approaching the rutting season

attracted by the bellowing of the stags the

Hinds gather at the traditional meeting points

these are usually spaces

that have not grown over

the Stags need open spaces to give

them room to impress the Highlands

and intimidate their rivals

the last big wetland area in Europe

is still a coherent mix of river and

flooding managed pasture and diverse nature

it's like looking into the past of our continent

that shows us how natural flood protection

for large towns and cities can be

as in the sava wetlands of Croatia

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